Internal telescopic tube locking device

ABSTRACT

A locking device for multiple-section telescoping tubes wherein a smaller tube is telescopically retractable into or extensible from within a larger tube includes a pair of opposing blocks, disposed within the telescoping tubes, one block being attached to the smaller tube, the other block being configured to move laterally with respect to the first block when the blocks are moved longitudinally with respect to each other. Depending on the direction of longitudinal movement of the blocks, one block may be caused to bear against an inner side of the larger tube to resist retraction of the smaller tube, or the blocks may be allowed to move away from the inner side of the larger tube to allow free sliding extension of the smaller tube. The device also includes means for selectively longitudinally moving one of the blocks with respect to the other, so as to allow free sliding retraction of the smaller tube, when desired.

[0001] The present application claims priority from United Statesprovisional patent application serial no. 06/420,126, filed on Oct. 22,2002, the disclosure of which is incorporated herein by reference in itsentirety.

BACKGROUND OF THE INVENTION

[0002] 1. Field of the Invention

[0003] The present invention relates generally to extendable supportmembers. More particularly, the present invention relates to an internallocking device for telescopic tube sections that provides secure lockingand does not require a release mechanism to be extended.

[0004] 2. Related Art

[0005] There are many types of support devices that utilize telescopingsupport legs, especially where the support devices are intended to beeasily portable. Such support devices include tripods, tables, easels,etc. Likewise, there are many forms of locking devices for telescopingsupport legs for these devices. One such leg-locking mechanism isdisclosed in U.S. Pat. No. 6,050,531, the disclosure of which isincorporated herein by reference in its entirety. Many such lockingdevices use clamp and bolt mechanisms, spring-loaded pins and holes,cam-lock devices, wing nut-operated clamps, threaded collar clamps,internal threaded studs, resilient washers, etc. Many of these requirerotation of a collar or of an individual leg section in order to lock orun-lock it from a given position. Some of them do not allow adjustableextension of the legs, but allow fixation of a leg only in designatedpositions. Others require external protrusions and parts that can falloff and become lost.

[0006] Additionally, some telescoping tube leg-locking devices arecumbersome and time-consuming to use, requiring several complicatedmaneuvers to lock or unlock a leg segment. Some prior leg-lockingdevices also require telescoping leg sections of a particularcross-sectional shape. Moreover, some have locking mechanisms that canbe relatively easily forced to move when in the locked position, thusproducing extreme wear, and reducing the useful life of the device.

SUMMARY OF THE INVENTION

[0007] The present invention advantageously provides a telescopic tubeleg-locking apparatus wherein the legs may be extended simply bypulling, and do not require a release mechanism.

[0008] The present invention also provides a telescopic tube leg-lockingapparatus that sequentially unlocks multiple tube or leg sections byactuating a single unlocking device to retract the legs to a telescopeclose position.

[0009] The invention also provides a telescopic tube leg-lockingapparatus that allows multiple tubes of any cross-section to be lockedand released.

[0010] The invention also provides a telescopic tube leg-lockingapparatus that is suitable for tubes of various cross-sectional shapes,and provides secure locking that is more difficult to force to move whenin the locked position, and thus reduces wear on the device.

[0011] In accordance with one embodiment thereof, the invention providesa locking device for multiple-section telescoping tubes wherein asmaller tube is telescopically retractable into or extensible fromwithin a larger tube. The locking device includes a pair of opposingblocks, disposed within the telescoping tubes, one block of the pairbeing attached to the smaller tube, the other block of the pair beingconfigured to move laterally with respect to the first block when theblocks are moved longitudinally with respect to each other. Depending onthe direction of longitudinal movement of the blocks, one block may becaused to bear against an inner side of the larger tube to resistretraction of the smaller tube, or the blocks may be allowed to moveaway from the inner side of the larger tube to allow free slidingextension of the smaller tube. The device also includes means forselectively longitudinally moving one of the blocks with respect to theother, so as to selectively allow free sliding retraction of the smallertube, when desired.

[0012] Additional features and advantages of the invention will beapparent from the detailed description which follows, taken inconjunction with the accompanying drawings, which together illustrate,by way of example, features of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0013]FIG. 1 is an end cross-sectional view of telescoping tube segmentsin one embodiment of the present invention.

[0014]FIG. 2 is a side cross-sectional view of the assembly of FIG. 1,showing the parts as assembled in the smaller two sections of atelescoping tube set.

[0015]FIG. 3 is an exploded view of the embodiment of FIGS. 1 and 2,showing how the various parts are assembled.

[0016]FIG. 4 is a side cross-sectional view of an embodiment of thetelescoping tube leg-locking device configured for round tubes.

[0017]FIG. 5 is an exploded view of the embodiment of FIG. 4.

[0018]FIG. 6 is a perspective view depicting another variation of a rampblock compatible with the system of FIG. 4, wherein the ramp block hastapered slots configured to receive spherical rollers.

[0019]FIG. 7 is an end view of the ramp block of FIGS. 4-5 or FIG. 6.

[0020] FIGS. 8-14 are side views of various other embodiments of theinternal locking mechanism in accordance with the present invention.

DETAILED DESCRIPTION

[0021] Reference will now be made to the exemplary embodimentsillustrated in the drawings, and specific language will be used hereinto describe the same. It will nevertheless be understood that nolimitation of the scope of the invention is thereby intended.Alterations and further modifications of the inventive featuresillustrated herein, and additional applications of the principles of theinventions as illustrated herein, which would occur to one skilled inthe relevant art and having possession of this disclosure, are to beconsidered within the scope of the invention.

[0022] Referring to FIGS. 1-3, the invention comprises an internallocking mechanism having a ramp block 1220, a release block 1230, arelease rod 1280, and a roller 1240. The ramp block includes a rampsurface 1370, and the release block includes an opposing ramp surface1380. The roller is disposed between the opposing ramp surfaces.Pressure of an optional spring 1250 (or gravity, if the tubes 1200, 1210are vertical, with foot 1320 down) biases the release block in thelocked position (toward the right in the figures), causing the roller tomove up along the ramp surfaces so as to force the release block awayfrom the ramp block and against the inner surface of the outer tube1200. Any action that would attempt to move the smaller inner tube 1210into the larger outer tube increases pressure of the release blockagainst the inside of the larger tube, thus increasing the locking forceholding the tubes in place.

[0023] While the embodiment of FIGS. 1-3 includes a single rollerdisposed between two opposing ramp surfaces, multiple rollers andmultiple corresponding ramp surfaces can be used to multiply force orprovide redundant structure, if desired. For example, as shown in FIG.9, the ramp block 1630 includes three ramp surfaces, and the releaseblock 1640 also includes three opposing ramp surfaces. Disposed betweenthese ramp surfaces are three rollers 1650. These rollers function inthe same manner as the roller 1240 in FIGS. 1-3. It will be apparentthat any number of ramp/roller combinations can be used. Additionally,while the ramp surfaces 1370, 1380 are shown as being angled withrespect to the length of the telescoping tubes, either or both opposingramp surfaces need not be angled, as will be apparent from thediscussion of alternative embodiments below.

[0024] The smaller inner tube 1210 can easily be extended withoutrelease by just pulling it out, with or without using the release button1290. To retract, the user slides the release button to the left. Therelease button is attached to a release rod 1280, which pushes againstthe release block 1230, moving it to the left in a slot 1390, allowingthe roller 1240 to move into a deeper part of the opposing ramps 1380and 1370. This relieves pressure of the release block against the insideof the outer tube 1200, allowing the smaller tube to slide into thelarger tube. Any number of tubing sections can be used, with eachrelease block releasing the next section when the release button iscontinually depressed. Alternatively, each section could release thenext, so that release is only needed until the first section is fullyretracted, after which the sections sequentially release each otherwithout continual pressure on the release button. It will be apparentthat where each section releases the next, some portion of the length ofeach section will need to be extended during use to keep the leg fromcollapsing.

[0025] As shown in FIG. 3, a plastic slide 1260 acts as a spacer betweenthe inner tube 1210 and the outer tube 1200, and also keeps the rampblock 1220 from sliding left or right. This slide is inserted through ahole 1340 and into a slot 1350 in the ramp block. A plastic glide 1265acts as a spacer between the tubes, and is inserted into the end of theouter tube. Round buttons 1270 and 1275 protrude from the glide, andsnap into holes in the outer tube to secure the glide in place. At fullextension of the smaller inner tube 1210, the upper right corner of therelease block 1230 hits the left edge of the plastic glide, which actsas stop to keep the smaller tube from sliding entirely out of the largertube 1200. An outward bulge on the button 1270 also provides constantpressure between the outer tube and a next larger size tube (not shown)to help keep the leg retracted when stored.

[0026] Shown in FIG. 4 is a side, cross-sectional view of an alternativeembodiment of the present invention configured for tubes 1440, 1490,1495 having a round cross-section. In this embodiment, the releaseportion 1420 of the release block 1400 is in the center of the releaseblock, and serves to actuate a spring stop 1410, also centered.Consequently, the tubes can axially rotate relative to each other andstill release. A stop ring 1435 stops the smaller tube and itsassociated ramp block 1480 regardless of radial orientation, but allowsthe release extension 1475 (corresponding to 1420) to pass through topush the next succeeding release block 1400 to the left, thus releasingit. Alternatively, the slide 1485 can keep the ramp from rotating sothat the stop ring 1435 is not needed.

[0027] The embodiment of FIG. 4 includes a cylindrical roller 1460 andflat ramp 1470. However, another embodiment of the round tubeleg-locking device shown in FIG. 6 comprises a ramp block 1500 havingone or more tapered slots 1520, with a spherical roller 1510 (i.e. aball bearing) in each slot, rather than the cylindrical roller andstraight ramp combination of FIG. 5. With this version, similar slotswould also be provided in a corresponding release block (not shown). Oneadvantage of the embodiment shown in FIGS. 6 and 7 is that it allows foreither multiple balls or a roller, and it is designed for multiplesections, thus the stop-ring 1435 and release extension 1475(corresponding also to 1420 in FIGS. 4 and 5) are added. Thesemodifications allow the leg locking mechanism in an upper tube to stopthe leg locking mechanism of a lower tube without releasing the upperrelease block (1400 in FIG. 4), unless the release rod 1280 pushes therelease extension through the stop-ring, putting pressure on the upperrelease block.

[0028] Depicted in FIGS. 8-14 are various other embodiments of internallocking mechanisms in accordance with the present invention. No tubesare shown in these variations, but they would function in a similar wayto the parts in FIG. 2. The variations shown in FIGS. 8 through 14function essentially the same as those of FIGS. 1-3 and 4-7, with themain difference being how they spread the ramps and release elementsapart. Each of these alternative variations use different roller andramp configurations to apply pressure to the inside of the outer tubewhen the (lower) ramp block is confined in the smaller tube, and the(upper) release block presses against the inside of the outer tube.

[0029] The embodiment of FIG. 8 comprises an eccentric (i.e.non-cylindrical) roller 1620 disposed between a ramp block 1600 andrelease block 1610. In this embodiment, the ramp surfaces of the rampblock and release block comprise roller pockets 1622 a, 1622 b that holdthe eccentric roller in place. The eccentric roller acts as a cam topush the release block away from the ramp block when the ramp blockmoves to the left relative to the release block, causing pressure on theinside of the larger tube. The embodiment of FIG. 10 is similar to thatof FIG. 8, but comprises a roller that is an eccentric gear 1680 thatmates with geared or toothed ramp surfaces on the ramp block 1660 andrelease block 1670. Advantageously, because the shape of the rollerprovides the desired cam action to push the ramp block and release blockaway from each other, the ramp surfaces need not be angled with respectto the long axis of the telescoping tubes.

[0030] The embodiments of FIGS. 11 and 12 also use rollers and rampsurfaces having intermeshing gear-like teeth. The embodiment of FIG. 11includes angled opposing ramp surfaces 1690 and 1700 with gear toothsurfaces, and a round geared roller 1710. The embodiment functions likethat of FIG. 2, except that the intermeshing gear teeth substantiallyprevent slippage between the roller and the ramp surfaces. Theembodiment of FIG. 12 has an angled geared ramp on the ramp block 1720,disposed opposite a non-angled geared ramp on the release block 1730. Around geared roller 1740 is disposed between the two ramp surfaces toprovide the outward locking force.

[0031] The embodiments of FIGS. 13 and 14 are also similar to that ofFIG. 8 in that a cam-type action is used. In the embodiment of FIG. 14,the rollers comprise angled plates 1800 disposed in pockets 1805 formedin the ramp block 1780 and release block 1790. The angled plates producea cam-type action that causes the release block to move toward the innersurface of the outer tube (not shown) as the release block moves toright relative to the ramp block. Finally, the embodiment of FIG. 13,incorporates a roller system comprising a hinge plate 1770 pivotallyattached on each side (the one shown and an identical one on theopposite side) of the ramp block 1750 and release block 1760, so that asthe ramp block and release block translate with respect to each other,the hinge plates pivot and cause the release block to move toward oraway from the ramp block to provide a cam-locking action. It will beapparent that other variations are also possible.

[0032] Each of the variations in FIGS. 8-14 also allow release with arelease mechanism similar to that of FIG. 2, and comprise single ormultiple locking mechanisms, as well as varied spring positions. Forexample, the spring can be located at either end of the ramp block andrelease block combination, as seen by comparing FIG. 14 with FIG. 11,for example. Alternatively, a spring could be disposed between opposingramp surfaces, adjacent to a roller, such as at position 1655 in FIG. 9.Other variations are also possible.

[0033] Advantageously, if extrusions are used to make the ramp block,the release block, and the roller for the various embodiments shown,these parts can be cut to the same length (e.g. 1″), which makesmanufacture and assembly simpler. Viewing FIG. 14, for example, plates1800 have the cross-section shown, and they would be rectangles 1″ wideby about ½″ tall, as shown. One exception to this is the embodiment ofFIG. 13, where the roller comprises two hinge plates 1770 that arepivotally connected with pins through holes in the release block andramp block, so as to hinge them together.

[0034] The present invention provides many advantages over the priorart. Viewing FIGS. 1-3, unlike the prior art, the release rod 1280 isnot connected to the release block 1230, such that the release button1290 need not be used to extend legs sections as well as retract them.Additionally, the retaining button 1270 of the leg glides 1265 istapered on the top to increase friction when the larger leg 1200 isretracted into the next larger section, so that it will not slide out ofthe next larger section when retracted, unless additional force isapplied to pull it out.

[0035] Another advantage of the present design is that the cutout 1330in the leg tube 1210 is simpler and can be cut out with a band sawinstead of a milling machine, thus lowering production costs. Assemblyof the ramp 1220 and release block 1230 is also somewhat easier than inthe prior art, also reducing cost and complexity. Finally, the surfacearea of the release block 1230 that presses against the outer tube islarger than the surface of a roller alone, thus eliminating or reducingdistortion of the thin-walled tubing that is more likely with a rolleracting directly on the inside of the tube.

[0036] As in the '531 patent, this design allows multiple leg sectionsto be telescopically connected, instead of just two leg sections. Someprior devices utilize similar mechanisms, but cannot be adapted to morethan two leg sections. Similarly, some other prior leg locking systemscan be used with multiple sections, but employ significantly differentleg-locking mechanisms. Additionally, also as in the '531 patent,locking is automatic as legs are extended, without the need for arelease. Releasing to retract leg sections is either automatic when theyare brought to parallel positions, or it is accomplished with a singlemotion by sliding a release toward the larger diameter sections,collapsing each section in turn. With the present invention, however,multiple tubes of any cross section can be locked and released.

[0037] With this design, while the roller is unlikely to wear, thespring or gravity bias of the release plate will probably cause a verysmall amount of wear on the plate itself and on the inside of the tube.However, the wear will be very slight, and is likely to be noticeableonly if the apparatus is used often for a very long time—probably muchlonger than the life of the user. Additionally, the design automaticallycompensates for wear, because the movement of the roller (and hence thelocking position) depends on the actual geometry of the ramp andrelease, not the intended geometry of those parts. Furthermore, anyshape tube can be accommodated with spherical or cylindrical rollers invariations of this design.

[0038] By way of example, in one embodiment the invention can bedescribed as a telescopic tube locking device for multiple-sectiontelescopic tubes. The device comprises a first tube section, and asecond tube section slidably assembled over the first tube section, thefirst tube being configured to selectively extend from or retract intothe second tube section. A clamping assembly is disposed within thefirst tube section, and includes (1) a ramp block fixedly attached tothe first tube section, the ramp block having a first ramp surface, (2)a movable release block slidably disposed opposite the ramp block andhaving a second ramp surface, and (3) a roller disposed between thefirst and second ramp surfaces. The ramp block and release block areconfigured such that relative translation of the release block in afirst direction rolls the roller up the first and second ramps so as tolock the clamping assembly, and relative translation in a seconddirection rolls the roller down the ramps so as to release the clampingassembly and allow sliding of the first tube within the second tube. Aspring is disposed between the ramp block and release block to bias therelease block in the first direction. The first tube section includes apush rod assembly slidably disposed therein and configured to contactthe release block to push it in the second direction against the spring.The clamping assembly is configured to release when (1) the push rod isused to push the release block, and (2) when the first tube is pulled ina direction to extend it from the second tube.

[0039] As another more detailed example, the device may include a secondclamping mechanism associated with a third tube section disposed aroundthe second tube section. The release block includes a release extensionconfigured to contact a second release block of the second clampingmechanism, so as to allow sequential retraction of the second tubesection into the third tube section following retraction of the firsttube section into the second tube section.

[0040] It is to be understood that the above-referenced arrangements areillustrative of the application for the principles of the presentinvention. Numerous modifications and alternative arrangements can bedevised without departing from the spirit and scope of the presentinvention while the present invention has been shown in the drawings anddescribed above in connection with the exemplary embodiments(s) of theinvention. It will be apparent to those of ordinary skill in the artthat numerous modifications can be made without departing from theprinciples and concepts of the invention as set forth in the claims.

What is claimed is:
 1. A telescopic tube locking device formultiple-section telescopic tubes, comprising: a tube section, having aninside; a smaller tube section, slidably disposed within the tubesection, configured to selectively extend from or retract into the tubesection; a clamping assembly, attached within the smaller tube section,having a locked position and a released position, the clamping assemblyincluding a ramp block, fixedly attached to the smaller tube section,the ramp block having a first ramp surface; a release block, moveablydisposed opposite the ramp block, having a second ramp surface oppositethe first ramp surface; and a roller, rollably disposed between thefirst and second ramp surfaces, configured to laterally spread the rampblock and release block to place the clamping mechanism in the lockedposition upon relative translation of the release block in a firstdirection; and a release mechanism, configured to release the clampingassembly when (i) the release block is pushed in a direction opposite tothe first direction, and (ii) the smaller tube section is pulled in adirection to extend it from the tube section.
 2. A device in accordancewith claim 1, further comprising: a larger tube section, disposed aroundthe tube section; a second clamping mechanism, associated with thelarger tube section, having a second release block, a locked position,and a released position; a release extension, associated with therelease block, configured to contact the second release block, so as torelease the second clamping mechanism and allow sequential retraction ofthe tube section into the larger tube section following retraction ofthe smaller tube section into the tube section.
 3. A device inaccordance with claim 1, wherein the roller is selected from the groupconsisting of substantially cylindrical rollers, substantially sphericalrollers, rollers having an eccentric cylindrical cross-section,cylindrical rollers with gear-type teeth, eccentric cylindrical rollerswith gear-type teeth, rocker plates, and a hinge plate pivotallyinterconnecting the ramp block and release block.
 4. A device inaccordance with claim 1, wherein the roller is substantially spherical,and the first and second ramp surfaces comprise tapered slots,configured to receive the spherical roller.
 5. A device in accordancewith claim 1, wherein the roller comprises gear-type teeth, and thefirst and second ramp surfaces comprise gear-type teeth configured tointermesh with the teeth of the roller.
 6. A device in accordance withclaim 1, wherein at least one of the first and second ramp surfaces arenon-angled with respect to the telescopic tubes.
 7. A device inaccordance with claim 1, wherein the roller comprises at least tworollers, each roller being disposed between opposing ramp surfaces.
 8. Adevice in accordance with claim 1, wherein the roller has an eccentriccross-section configured to produce a cam-type action between the rampsurfaces when rotated.
 9. A device in accordance with claim 8, whereinthe roller comprises gear-type teeth, and the first and second rampsurfaces comprise gear-type teeth configured to intermesh with the teethof the roller.
 10. A device in accordance with claim 8, wherein the rampblock and release block include a pocket for holding opposing edges ofthe roller.
 11. A telescopic tube locking device for multiple-sectiontelescopic tubes including a larger tube section having an inside, and asmaller tube section slidably disposed within the larger tube sectionand configured to selectively extend from or retract thereinto, thelocking device comprising: a ramp block, fixedly attached within thesmaller tube section, the ramp block having a first ramp surface; arelease block, moveably disposed against the inside of the larger tubesection opposite the first ramp block, the release block having a secondramp surface; and a roller, disposed between the first and second rampsurfaces, the ramp block and release block being configured such thatrelative longitudinal translation thereof moves the roller so as toeither (i) press the release block in a locking direction laterally awayfrom the ramp block and against the inside of the larger tube section tolock the smaller tube section therein, or (ii) allow the release blockto move in a release direction laterally toward the ramp block, so as toreduce pressure on the release block and allow sliding of the smallertube section within the larger tube section.
 12. A device in accordancewith claim 11, further comprising a push rod, slidably disposed withinthe smaller tube section, configured to contact the first release blockto push it in the release direction.
 13. A device in accordance withclaim 11, wherein the multiple-section telescopic tube includes alargest tube section disposed around the larger tube section, thelocking device further comprising: a second ramp block, fixedly attachedwithin the larger tube section, the second ramp block having a thirdramp surface; a second release block, moveably disposed against aninside surface of the largest tube section opposite the second rampblock, the second release block having a fourth ramp surface; a secondroller, disposed between the third and fourth ramp surfaces, the secondramp block and second release block being configured such that relativelongitudinal translation thereof moves the roller so as to either (i)press the second release block in a locking direction laterally awayfrom the second ramp block and against the inside of the largest tubesection to lock the larger tube section therein, or (ii) allow thesecond release block to move in a release direction laterally toward thesecond ramp block, so as to reduce pressure on the second release blockand allow sliding of the larger tube section within the largest tubesection; and a release extension, associated with the release block,configured to contact the second release block, so as to allowsequential retraction of the larger tube section into the largest tubesection following retraction of the smaller tube section into the largertube section.
 14. A device in accordance with claim 11, wherein theroller is selected from the group consisting of substantiallycylindrical rollers, substantially spherical rollers, rollers having aneccentric cylindrical cross-section, cylindrical rollers with gear-typeteeth, eccentric cylindrical rollers with gear-type teeth, rockerplates, and a hinge plate pivotally interconnecting the ramp block andrelease block.
 15. A device in accordance with claim 14, wherein theroller comprises an eccentric cross-section cylindrical roller or arocker plate, and the ramp block and release block include a pocket forholding opposing edges of the roller.
 16. A device in accordance withclaim 15, wherein the roller comprises gear-type teeth, and the firstand second ramp surfaces comprise gear-type teeth configured tointermesh with the teeth of the roller.
 17. A device in accordance withclaim 11, wherein at least one of the first and second ramp surfaces arenon-angled with respect to the telescopic tubes.
 18. A device inaccordance with claim 11, wherein the roller comprises at least tworollers, each roller being disposed between opposing ramp surfaces. 19.A locking device for multiple-section telescoping tubes including asmaller tube that is telescopically retractable into or extensible fromwithin a larger tube, comprising: a pair of opposing blocks, disposedwithin the telescoping tubes, one block of the pair being attached tothe smaller tube, the other block of the pair being configured to movelaterally with respect to the aforementioned block when the blocks aremoved longitudinally with respect to each other, so as to (i) cause oneblock to bear against an inner side of the larger tube to resistretraction of the smaller tube, and (ii) allow the blocks to move awayfrom the inner side of the larger tube to allow free sliding extensionof the smaller tube; and means for selectively longitudinally moving oneof the blocks with respect to the other, so as to selectively allow freesliding retraction of the smaller tube.
 20. A locking device inaccordance with claim 19, wherein the means for selectivelylongitudinally moving one of the blocks comprises a push rod, slidablydisposed within the smaller tube, configured to contact one of theblocks to cause the blocks to move away from the inner side of thelarger tube.